Chapter 5 : The Chapter 5 : The Periodic TablePeriodic Table

ObjectivesObjectives Be able to define and explain each Be able to define and explain each

periodic trend, including comparing periodic trend, including comparing two different elements. For example: two different elements. For example: which of the following elements has which of the following elements has the larger atomic radius?the larger atomic radius?

History of the Periodic Table History of the Periodic Table

In the 1700s In the 1700s scientists had scientists had identified only identified only 30 elements30 elements

In the 1800s In the 1800s there were 60there were 60

History of the Periodic Table History of the Periodic Table

Early 1800s Early 1800s Dobereiner grouped Dobereiner grouped elements into triads elements into triads by physical and by physical and chemical propertieschemical properties

Li, Na, KLi, Na, K

History of the Periodic Table History of the Periodic Table 1865 J.A.R. Newlands 1865 J.A.R. Newlands

discovered that when discovered that when elements were elements were arranged by atomic arranged by atomic mass, properties mass, properties repeated themselves repeated themselves every eighth element every eighth element

Called these octavesCalled these octaves

Mendeleev Mendeleev 1869 Dmitri Mendeleev 1869 Dmitri Mendeleev

produced the first periodic produced the first periodic table for his studentstable for his students

Left blanks where Left blanks where elements had yet to be elements had yet to be discovereddiscovered

Not strictly in order of Not strictly in order of atomic mass (Ar atomic mass (Ar K)K)

Properties of Germanium as Predicted by Mendeleev

Properties ofEkasilicon

Predictedin 1871

Atomic weightDensity  

Specific heatMelting pointOxide formula  

Oxide density  

Chloride formula  

bp of chloride

725.5 g/cm3

0.31 J/(°C · g)Very highRO2

4.7 g/cm3

RCl4

100°C

Properties ofGermanium

Predictedin 1871

Observed  in1886

Atomic weightDensity  

Specific heatMelting pointOxide formula  

Oxide density  

Chloride formula  

bp of chloride

725.5 g/cm3

0.31 J/(°C · g)Very highRO2

4.7 g/cm3

RCl4

100°C

72.35.47 g/cm3

0.32 J/(°C · g)960°CGeO2

4.70 g/cm3

GeCl4

86°C

MoseleyMoseley In 1913 Moseley In 1913 Moseley

assigned elements assigned elements atomic numbers and atomic numbers and rearranged periodic tablerearranged periodic table

Periodic LawPeriodic Law – when – when arranged by increasing arranged by increasing atomic number elements atomic number elements show periodic trendsshow periodic trends

Table TermsTable Terms Groups or Families Groups or Families are the are the

columns on the periodic tablecolumns on the periodic table Periods Periods are the rows going across.are the rows going across.

Periodic PropertiesPeriodic Properties Depend on two main factors: the Depend on two main factors: the

number of protons and electrons, number of protons and electrons, and the way these subatomic and the way these subatomic particles interact with each other.particles interact with each other.

Draw a Bohr Model forDraw a Bohr Model for LithiumLithium PotassiumPotassium FluorineFluorine Make sure to indicate the number of Make sure to indicate the number of

protons in the centerprotons in the center Make sure levels are the same size Make sure levels are the same size

from atom to atom (rings for energy from atom to atom (rings for energy levels should be the same size)levels should be the same size)

LithiumLithium

PotassiumPotassium

FluorineFluorine

Atomic RadiusAtomic Radius Atomic radiusAtomic radius is the distance from the atom’s nucleus is the distance from the atom’s nucleus

to its outer edge.to its outer edge. Simply can be thought of as the size of an atomSimply can be thought of as the size of an atom Using the Bohr model, and thinking about the number, Using the Bohr model, and thinking about the number,

arrangement, and interaction of the protons and arrangement, and interaction of the protons and electrons, answer the following questions, and explain electrons, answer the following questions, and explain your answersyour answers

Which atom has a larger atomic radius: lithium or Which atom has a larger atomic radius: lithium or potassium?potassium?

Which atom has a larger atomic radius: lithium or Which atom has a larger atomic radius: lithium or fluorine?fluorine?

What is the atomic radius ____ from left to right on the What is the atomic radius ____ from left to right on the periodic table.periodic table.

What is the atomic radius ____ from top to bottom on the What is the atomic radius ____ from top to bottom on the periodic table.periodic table.

Atomic RadiusAtomic Radius Atoms get larger going down a group Atoms get larger going down a group

or familyor family– Principle energy level increases Principle energy level increases

moving downmoving down Atoms get smaller moving from left Atoms get smaller moving from left

to rightto right– In the same energy level, more In the same energy level, more

protons exert a stronger pull protons exert a stronger pull towards the nucleustowards the nucleus

Ionization EnergyIonization Energy Ionization energy Ionization energy is the energy needed to is the energy needed to

remove one electronremove one electron Na(Na(gg) -> Na) -> Na++((gg) + 1e) + 1e-- Remember that an ion is a atom with an Remember that an ion is a atom with an

overall charge of negative or positive overall charge of negative or positive (number of electrons changes)(number of electrons changes)

Metals are more likely to give up an Metals are more likely to give up an electron than nonmetals.electron than nonmetals.

The more difficult it is to remove an electron The more difficult it is to remove an electron the higher the ionization energy will be.the higher the ionization energy will be.

Ionization Ionization Using the Bohr models, and thinking about the Using the Bohr models, and thinking about the

number, arrangement, and interaction of the number, arrangement, and interaction of the protons and electrons, answer the following protons and electrons, answer the following questions, and explain your anwsers.questions, and explain your anwsers.

Which atom has a higher ionization energy: Which atom has a higher ionization energy: lithium or potassium?lithium or potassium?

Which atom has a higher ionization energy: Which atom has a higher ionization energy: lithium or fluorine?lithium or fluorine?

Ionization energy______ from left to right on the Ionization energy______ from left to right on the perioidic tableperioidic table

Ionication energy _______from top to bottom on Ionication energy _______from top to bottom on the periodic tablethe periodic table

Ionization EnergyIonization Energy Ionization energy Ionization energy is the energy needed to is the energy needed to

remove one electronremove one electron Na(Na(gg) -> Na) -> Na++((gg) + 1e) + 1e-- Metals are more likely to give up an electron Metals are more likely to give up an electron

than nonmetals.than nonmetals. IE decreases when moving down the groupIE decreases when moving down the group IE increases moving from left to right in a IE increases moving from left to right in a

periodperiod There are second and third IEs for the next There are second and third IEs for the next

electronselectrons

Electron AffinityElectron Affinity Electron affinity Electron affinity is the energy change is the energy change

that occurs when an atom gains an electronthat occurs when an atom gains an electron F(F(gg) + e) + e-- F F-- ( (gg) ) Most atoms give off energy when an Most atoms give off energy when an

electron is gained (negative)electron is gained (negative) Nonmetals have more of an electron Nonmetals have more of an electron

affinity than metalsaffinity than metals Atoms with greater affinity are more able to Atoms with greater affinity are more able to

gain valance electronsgain valance electrons

Electron AffinityElectron Affinity Using the Bohr models, and thinking about the Using the Bohr models, and thinking about the

number, arrangement, and interaction of the number, arrangement, and interaction of the protons and electrons, answer the following protons and electrons, answer the following questions, and explain your answers.questions, and explain your answers.

Which atom has a greater electron affinity: Which atom has a greater electron affinity: lithium or potassium?lithium or potassium?

Which atom has a greater electron affinity: Which atom has a greater electron affinity: lithium or fluorine?lithium or fluorine?

Electron affinity _______ from left to right on the Electron affinity _______ from left to right on the periodic table.periodic table.

Electron affinity ______from top to bottom on the Electron affinity ______from top to bottom on the periodic tableperiodic table

Electron affinityElectron affinity EA decreases when moving down EA decreases when moving down

the groupthe group EA increases moving from left to EA increases moving from left to

right in a periodright in a period

ElectronegativityElectronegativity Electronegativity Electronegativity reflects an atom’s ability to reflects an atom’s ability to

attract electronsattract electrons It is defined as the ability of an atom in a molecule to It is defined as the ability of an atom in a molecule to

attract electrons.attract electrons. Example: if a molecule consists of atoms X bonded to Example: if a molecule consists of atoms X bonded to

atom Y.atom Y. X-YX-Y The two atoms share the electrons in the molecule. The two atoms share the electrons in the molecule.

If X is more electronegative than Y, then the If X is more electronegative than Y, then the electrons will be more strongly attracted to X than Y, electrons will be more strongly attracted to X than Y, and will “hog” the electronsand will “hog” the electrons

X – YX – Y

ElectronegativityElectronegativity Which atom has a greater Which atom has a greater

electronegativity: lithium or potassium?electronegativity: lithium or potassium? Which atom has a greater Which atom has a greater

electronegativity: lithium or fluorine?electronegativity: lithium or fluorine? Electronegativity _______ from left to Electronegativity _______ from left to

right on the periodic table.right on the periodic table. Electronegativity______ from top to Electronegativity______ from top to

bottom on the periodic tablebottom on the periodic table

ElectronegativityElectronegativityCs & Fr have the lowest Cs & Fr have the lowest

electronegativities; F has the electronegativities; F has the highesthighest

EN decreases when moving EN decreases when moving down the groupdown the group

EN increases when moving from EN increases when moving from left to right across the periodleft to right across the period

Ionic RadiusIonic Radius Ionic radiusIonic radius is the distance from the ion’s is the distance from the ion’s

nucleus to its outer edge.nucleus to its outer edge. Remember that positive ions are formed Remember that positive ions are formed

when atoms lose electronswhen atoms lose electrons Negative ions are formed when atoms gain Negative ions are formed when atoms gain

electronselectrons Ions get larger going down a group or Ions get larger going down a group or

familyfamily Ions get larger moving from left to rightIons get larger moving from left to right

– The more electrons added increases repulsion The more electrons added increases repulsion among themamong them

Draw the Bohr models for the Draw the Bohr models for the following:following:

Lithium and Lithium ion (+)Lithium and Lithium ion (+) How does the lithium ion’s radius compare How does the lithium ion’s radius compare

to the radius of neutral lithium?to the radius of neutral lithium? Chlorine and Chlorine ion (-)Chlorine and Chlorine ion (-) How does the chloride ion’s radius How does the chloride ion’s radius

compare to the radius of neutral chlorine?compare to the radius of neutral chlorine? Sodium ion (+) and Fluoride Ion (-)Sodium ion (+) and Fluoride Ion (-) How do the number of electrons in these How do the number of electrons in these

two ions compare to each other?two ions compare to each other? How do the radii of these two ions How do the radii of these two ions

compare to each other?compare to each other?

Ionic radiusIonic radius Ions get larger going down a Ions get larger going down a

group or familygroup or family Ions get larger moving from Ions get larger moving from

left to rightleft to right– The more electrons added The more electrons added

increases repulsion among increases repulsion among themthem

Major Groups on the Periodic Major Groups on the Periodic TableTable

Alkali MetalsAlkali Metals Alkaline Earth Alkaline Earth

MetalsMetals Transition Metals Transition Metals Boron GroupBoron Group Carbon GroupCarbon Group Nitrogen GroupNitrogen Group

Oxygen Group Oxygen Group (Chalcogens)(Chalcogens)

HalogensHalogens Noble GasesNoble Gases Actinide SeriesActinide Series Lanthanide Lanthanide

SeriesSeries

Reactivity of Alkali and Alkaline Reactivity of Alkali and Alkaline Earth MetalsEarth Metals

Metals become Metals become more reactive as more reactive as you move down you move down the groupthe group

Metals become Metals become less active when less active when moving left to moving left to rightright

Why Are There Patterns?Why Are There Patterns? Elements have physical and chemical Elements have physical and chemical

properties based upon their valence properties based upon their valence electrons.electrons.

Valence electronsValence electrons are the electrons in are the electrons in the outer most energy level (s & p the outer most energy level (s & p orbitals)orbitals)

The number of valence electrons may The number of valence electrons may be determined by using the periodic be determined by using the periodic tabletable

Why Are There Patterns?Why Are There Patterns? When you look at an atom you are When you look at an atom you are

observing the valence electronsobserving the valence electrons Duet rule - only 2 electrons fill the Duet rule - only 2 electrons fill the

first energy levelfirst energy level Octet rule – 8 valence electrons is Octet rule – 8 valence electrons is

considered to be a full setconsidered to be a full set